1. Field of the Invention
The present invention relates to a method for controlling the filling rate in a filling machine. More specifically, the present invention relates to a filling method in which bottles are fed into a rotary table and a predetermined amount of a substance is filled in each bottle while the rotary table makes one rotation, said method being characterized by the features that just before withdrawing the filled bottles from the rotary table, the proportion of completely filled bottles is detected by two filling completion detecting devices defining a central angle .theta. of 10.degree. to 30.degree. with respect to the center of the rotary table and the rotation speed of the rotary table is increased or decreased based on the results of the detections.
2. Description of the Prior Art
According to conventional methods for filling liquids into bottles, bottles are fed onto a rotary table, filling nozzles are inserted into the bottles and filling is completed while the rotary table makes one rotation, and the filled bottles are withdrawn from the rotary table. If feeding of bottles to the rotary table and withdrawal of filling-completed bottles therefrom is continuously performed, a continuous filling operation becomes possible and the operation efficiency can be remarkably increased.
In most of the conventional filling machines, however, the rotation speed of the table is set at an appropriate level and the continuous filling operation is conducted at a constant speed without controlling or adjusting the operation speed during the filling operation which is continuously conducted. If the dimensions of the bottles and/or the physical properties of the liquid substance to be filled therein do not change, but rather remain uniform, and if the predetermined rotation speed corresponds substantially to the maximum capacity of the filling machine, no particular disadvantage is caused. However, because the viscosity or other physical characteristics of the liquid may change in response to changes of the ambient temperature or the like, it is necessary to provide a certain margin of safety when the rotation speed of the rotary table is set. In other words, it is difficult always to perform the operation at a rotation speed corresponding to the maximum filling capacity of the filling machine. For example, if the rotation speed of the rotary table is set too high, there will be a risk that the quantity of the liquid filled in the bottles will become too small when the ambient temperature becomes lower.
According to the present invention, it is possible always to perform the filling operation at the maximum filling capacity of the filling machine consistent with always completely filling the bottles with the required amount of liquid. An embodiment of the present invention will now be described by reference to the accompanying drawings.